The shrimp Crangon crangon is a significant predator of the smallest sizes of plaice during and immediately after the fish settle on sandy beaches. Predation rate is strongly dependent on the size of both the predator and the prey (Gibson, Yin & Robb 1995). Polychaete worms are dominant predators within the substratum and tend to be opportunistic and actively pursue prey (although they may have size preferences); their numbers may be closely related to those of their prey, which includes other worms and crustaceans (Meire et al. 1994). Many infaunal species also scavenge e.g. Nephtys and the isopod Eurydice pulchra and quantity of food available determines the density of scavengers (Hayward 1994; Ansell et al. 1972).

The presence of high densities of adult invertebrates in the sand may inhibit the recruitment of potential colonising stages from the water column (Olafsson, Peterson & Ambrose 1994). This may account for juveniles occupying less favourable parts of the intertidal areas, for example juvenile Arenicola and Nephtys settle in areas outside the optimal distribution for the adults (usually higher on the shore).

Sandflat communities tend to be relatively poor in species but may have very high abundances of those species which are present.

None.

Intertidal areas are well defined as juvenile fish-feeding areas (Costa & Elliott 1991). Sheltered sandflats are important nursery areas for plaice (Lockwood 1972; Marshall 1995; Marshall & Elliott 1997), as well as feeding areas for sea bass Dicentrarchus labrax and flounder Platichthys flesus (Elliott & Taylor 1989). Fish such as sole Solea solea and gadoids frequent sandy areas, but many also occur on coarser and mixed grades of sediment. The most important marine predators on intertidal sandflats are the sole Solea solea, dab Limanda limanda, flounder Platichthys flesus and plaice Pleuronectes platessa plaice which feed on polychaetes (for example Arenicola and Nereis) and tidally active crustaceans such as Bathyporeia and Eurydice species (Croker & Hatfield 1980; McDermott 1983; McLachlan 1983). In summer, large numbers of juvenile plaice and dab move over flats at high tide to feed on mobile epifauna, sedentary infauna and protruding siphons and tentacles (Elliott & Taylor 1989). On sandflats many demersal fish are opportunistic predators and the prey choice will reflect the infaunal species distribution of the area (Costa & Elliott 1991). Migratory species of fish such as salmon and shad can be found on sandflats when on passage to other wetlands e.g. saltmarshes and freshwater areas, although they appear to have no particular requirement for the sandflats.

The littoral gravel and sand biotopes are also used by important wintering and passage birds for feeding. Shorebirds are important predators on north-west European intertidal sandflats during long migrations from breeding to wintering grounds. Intertidal sandflats also support microphytobenthos in the interstices between the sand grains. Mucilagenous secretions produced by these algae may stabilise fine substrata (Tait & Dipper 1998). Macrophytes are usually sparse on intertidal sand unless there are some stones or shells for the attachment of species. The community may include mats of Enteromorpha spp. and Ulva spp., possibly in large aggregates to form the so-called ‘green tides’ (Piriou, Menesguen & Salomon 1991).

No information available.

No information available.

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